Lubricating oils containing alkylated phenoxy acid derivatives



United States Patent 3,360,464 LUBRICATING OILS CONTAINING ALKYLATEDPHENOXY ACID DERIVATIVES Ferdinand P. Otto, Jr., Woodbury, N.J.,assignor to Mobil Oil Corporation, a corporation of New York No Drawing.Filed Aug. 2, 1965, Ser. No. 476,653 5 Claims. (Cl. 252-515) Thisinvention relates to improved lubricating oil compositions andparticularly to lubricating oil compositions containing noveldetergents, and to the method of making them.

It is well recognized that mineral oils used as lubricants in modernengines tend to oxidize during use. The products of such oxidation areacids which can corrode the metal parts of the engine. The oxidation,moreover, results in the formation of heavy sludge, hard lacquers andthick adhesive deposits inside the engine, especially around the pistonsand other moving parts. These substances seriously interfere with theefiicient performance of the engine.

Agents are generally added to lubricants to prevent the sludge, lacquersand adhesive deposits from settling. These agents, known as detergents,keep the oxidation products suspended or dispersed in the oil therebypermitting the engine to operate freely. One group of highly eifectivedetergents are complex metal salts. However, while such agents performsatisfactorily, these detergents may themselves deteriorate underextreme engine conditions, leav ing ash-like deposits inside the engine.Some metallic detergents even contribute to the formation of acids inthe lubricating oil. It would therefore be desirable to providedetergents which do not form deposits during use.

A major object of this invention is to provide novel lubricating oilcompositions which possess detergent properties. A further object is toprovide novel lubricating oil compositions which contain non-ash formingdetergents. Another object is to provide novel non-metallic reactionproducts which may be added to lubricating oil for enhancing thedetergent properties of the oils.

These and other objects I accomplish by adding to a major proportion ofa lubricating oil a minor proportion of an ester, amide, alkanolamide,or imidazoline of a polyalkylphenoxymonocarboxylic acid compound. Theacid compound is reacted with an alcohol, an amine, or an alkanolamino,to produce these novel products. The products are non-metallic, and yetthey exhibit excellent detergent properties.

Broadly, the compounds of this invention are prepared from apolyalkylphenoxymonocarboxylic acid compound wherein the polyalkylradical is a polyalkylene. The phenol precursor may be otherwiseunsubstituted or it may have other ring substitution, besides thepolyalkylene. This phenol, in the form of an alkali metal phenate, isreacted with a carboxylic compound to form the phenoxy acid compound orthe metal salt of the phenoxy acid compound. The phenoxy acid compound,also termed ether acid compound, is reacted with the alcohol, amine, oralkanolamine to form the final product.

The exact structures of these novel detergent compounds are not knownwith certainty. However, it is believed the compounds have the followinggeneral formula:

wherein R is an organic radical, such as alkyl, cycloalkyl, aralkyl,aryl and alkaryl, the alkyl radicals having from Patented Dec. 26, 19671 to 20 carbon atoms; R is a polyalkylene radical, includingpolyethylene, polypropylene, polybutylene, polyisobutylene, andpolyamylene having a molecular weight of about 500 to 3,000, andpreferably from about 750 to 1200; Z is alkoxy, amino, alkanolamino orheterocyclic amino having from 1 to about 20 carbon atoms; In is from 0to 4; and n is an integer of from 1 to about 19. The products may,therefore, include esters, amides, or alkanolamides of polyalkylphenoxymonocarboxylic acids. The preferred products are those wherein m is 0,the hydrogen atoms of the polyalkylphenol nucleus being unsubstituted.

More precisely, the formation of the compounds within the scope of thisinvention involves the steps of (1) alkylating a phenol with apolyalkylene compound in a mol ratio of about 0.1 to about 10 moles ofphenol to 1 mole of polyalkylene, but preferably using up to a 50% molarexcess of phenol; (2) reacting the resulting polyalkylphenol as analkali metal phenate, with a monocarboxylic compound having from 2 toabout 20 carbon atoms and a phenol-reactive functional group to producea phenoxy acid compound; and (3) reacting the phenoxy acid formed instep 2 with from about 0.5 to about 2.0 moles of an alcohol, an amine,or an alkanolamine per mole of the acid.

In the first step of my preferred reaction sequence, the polyalkylenecompound and the phenol are mixed together with moderate heating. Acatalyst suitable for such alkylation reactions, such as aluminumchloride, boron trifluoride etherate or phenolate, or the like, is addedslowly into the reaction mixture, under agitation. The temperature israised to a range of approximately from to C. and maintained for anextended period, the temperature increase being preferably performedgradually or in stages. When the reaction is complete, the mass iscooled slightly and the diluted mixture is washed free of unreactedmaterials with water. The wash water and solvent are removed bystripping, preferably under an inert atmosphere. This reaction and theproducts prepared thereby are described fully in copending patentapplication Ser. No. 41 8, 524, filed Dec. 15, 1964.

The resulting polyalkylphenol has the formula wherein R, R and m havethe above definition. This compound is first converted into an alkalimetal phenate and then reacted with the desired carboxylic compound. Thephenol is heated in the presence of an alkali metal alkoxide, such assodium ethylate or sodium isopropyl-ate to produce the metal phenate.Either the metal alkoxide or a mixture of alcohol and metal is firstintroduced into the reactor. The polyalkylphenol usually admixed with aliquid diluent, such as a process mineral oil, is then added. Excessalcohol is preferably removed from the reactor by stripping. Thecarboxylic compound is then added, preferably in excess of up to twicethe stoichiometric requirement, and the resulting mixture is heatedunder reflux conditions to form the phenoxy carboxylic acid product. Incertain cases the product is in the form of the metal salt. The reactionmixture should be therefore neutralized with an acid, such ashydrochloric acid, to convert the metal salt to the acid. Thereafter,the reaction mass is heated to remove water formed during the reaction;solids are filtered out of the liquid mass, still hot; and a finalstripping action is performed.

In the third step, the refined polyalkylphenoxy carboxylic compound isreacted with an ester, an amine or an alkanolamine. The preferred moleratio of reactants ranges 0.5 to 2.0 moles of the latter per mole ofcarboxylic compound. The reaction may be catalyzed with small amounts ofan acidic catalyst, such as paratoluene sulfonic acid. Heat is appliedand water of reaction is taken off as distillate, preferably in anazeotropic mixture with an inert organic diluent which may be present inthe reaction mass. The temperatures may range from 125 C. to 250 C.during the reaction and distillation steps. The resulting product iswashed free of unreacted components with hot distilled water. Smallquantities of antifoarning or demulsifying agents may be included, ifdesired. The remaining mixture is filtered while still hot, andthereafter the organic solvent is stripped off.

With respect to the polyalkylenes which may be used in this invention,those described in the above copending application are included.Polyalkylenes having a repeating alkyl unit of 3 to 5 carbon atoms, suchas polypropylene, polybutene, and polyisobutylene may be used. Themolecular weights may range from about 500 to 3,000, and preferably 750to 1200. A preferred reactant is polypropylene, With a molecular weightof between 750 and 850. The phenol with which the polyalkylene isreacted initially may be phenol, an alkyl or cycloalkyl phenol, or anaphthol or other aromatic-substituted phenol.

The metal alkoxide may be any of the alkali metal alcoholates made fromalcohols having from 1 to about 5 carbon atoms, and preferably from 2 to3. The carboxylate compound may have from 2 to about 20 carbon atoms.These include the lactones, such as propriolactone and butyrolactone,halocarboxylic acids, such as chloroacetic acid, and other similarcarboxylic compounds having functional groups which will react with ametallic phenate to form the phenoxy acid or phenoxy acid salt. If thelactone reactant is employed, it is believed that the metal salt isproduced. Therefore the product is acid-treated to convert it to theacid form. If the halocarboxylic acid is employed, the metal isdisplaced during the reaction as a metal halide. The carboxylatecompound may be straight-or branched-chain or alicyclic.

In the third step, the alcohol, amine or alkanolamine reactant may beany aliphatic compound having from 1 to about 20 carbon atoms. Mypreferred rectants include the polyamines, such as diethylene triamineand tetra- .ethylene pentamine, and the alkanolamines, such asdiet-hanolamine and triethanolamine. In the case of the polyaminereactant, there is indication that instead of only the simple amidebeing formed, all or at least a portion of the product consists of animidazoline substance. This, too, has proven to be a valuablelubricating oil detergent. Hence, the products of this invention includenot only esters, amides, and alkanolamides, but also cyclicizedproducts, such as an imidazoline product. As I have indicatedheretofore, the exact structures of these specific final products arenot known with certainty. It is believed, however, that the reaction ofstep III produces compounds having the above-disclosed general productformula.

The invention may be better illustrated by the following specificexamples, although the examples are not intended as a limitationthereof.

Example l.-Alkylation of phenol Into a four-necked flash equipped with astirrer, condenser, addition funnel, and thermometer were added 4860grams (6 moles) of polypropylene having a molecular weight of about 810and 705 grams (7.5 moles) of phenol. The mixture was heated to 50 C. and278 grams of boron trifluoride etherate were added gradually through theaddition funnel. The temperature was raised to 80 C. and held for 20hours, then to 100 C. for 4 hours.

The resulting reaction mass was quenched with 500 ml. of water to atemperature of 80 C. and diluted with 2500 ml. of toluene. The toluenesolution was washed with hot water until the washings were neutral tolitmus paper, and the washed solution was filtered. Residual water andsome toluene were stripped off, under nitrogen,

4 to 170 C. at atmospheric pressure, and the remaining toluene wasremoved at 175 C. and below 1 mm. Hg.

The product was analyzed for active hydrogen with the followingresults-Calcd, 1.10 mm. active hydrogen/ gram sample. Found: 0.69 mm.active hydrogen/gram sample. Percent yield: 62.8 based on activehydrogen.

Example ll.Preparati0n of polypropylphenoxybutyric acid Into a reactorsimilar to that used in Example I were added 1650 ml. of isopropylalcohol and 29.1 grams (1.7 moles) of metallic sodium, and the mixturewas heated to reflux until all of the sodium had dissolved. Theresulting solution was cooled to room temperature and a mixture of 3450grams of a process mineral oil and 2300 grams (1.7 moles) of thepolypropylphenol was stirred in. Excess isopropyl alcohol was removed bystripping the reaction mixture under nitrogen to a temperature of 200 C.

The remaining mass was cooled to 150 C. Intothis mixture were stirred253 grams (2.94 moles) of butyrolactone and the reaction mass was heatedto reflux for 5 hours at 175 C. Thereafter, the temperature was reducedto 106 C. and 230 ml. of concentrated hydrochloric acid was added. Waterwas distilled off at 180 C., under a nitrogen atmosphere. The remainingmass Was cooled to C., 250 grams of Hyfio (a diatomaceous earthfilter-aid) were added and the mass was filtered through an electricallyheated Hyflo-precoated Biichner funnel. The filtrate was then strippedunder nitrogen, to 175 C. at 5 mm. Hg.

The acid number of the remaining product was 14.5 mgm. of KOH per gramof oil-containing product.

Example III.Preparation of an amide with diethanolamine A mixture of 278grams (2.65 moles) of diethanolamine, 5117 grams (1.325 moles) of thepolypropylphenoxybutyric acid product of Example II, containing about60% of the process mineral oil, 1300 ml. of xylene, and 4 grams ofparatoluene sulfonic acid was heated and stirred, under nitrogen, in areaction flask equipped with a Dean-Stark take-off tube. During theheating, the temperature increased from C. to 200 C. over a 12- hourperiod. The mass was then held at 225 C. for one hour.

The xylene solution, containing the reaction product, was washed withsix one-liter portions of hot, distilled water; n-butyl alcohol wasadded to the water to break emulsion forming during the washing step.When the washings were neutral to litmus, 100 grams of Hyflo were addedand the product was filtered as in Example II. The product was strippedunder nitrogen to 175 C., at 5 to 6 mm. Hg.

The product was analyzed for nitrogen content and acid number with thefollowing results:

Total nitrogen=0.32%. Basic nitrogen=0.17%. Acid number=0.25 mgm. KOHper gram of product.

Example I V.Preparati0n of an amide with triethanolamine Usingprocedures similar to that of Examples I to III, a polypropylphenol wasprepared with an active hydrogen value of 0.70 mm. hydrogen per gram.This product was reacted with butyrolactone to form apolypropylphenoxybutyric acid in 60% of process mineral oil, with anacid number of 15 mgm. KOH per gram of oil-diluted product.

A mixture of 3200 grams (0.86 mole) of the polypropylphenoxybutyricacid, 1300 ml. of xylene, 262.4 grams (1.76 moles) of triethanolamine,and 8.5 grams of paratoluene sulfonic acid was refluxed for 3 hours atC.; water was removed in a Dean-Stark take-01f tube. Xylene wasdistilled off under nitrogen at 200 C. and atmospheric pressure. Theremaining reaction product was heated for 2 hours at 200 C. and for onehour at 225 C. The reaction mass was cooled to room temperature anddissolved in 2 liters of toluene. This solution was washed with 8one-liter portions of hot, distilled water, until washings were neutralto litmus. The remaining solution was heated to 175 C. at 130 mm. Hg andthen to 175 C. at 5 mm. Hg to remove the organic solvents.

The product was analyzed as in Example III.

Total nitrogen=0.31%. Basic nitrogen=0.27%. Acid number=0.76 mgm. KOHper gram of product.

Example V.Preparatin of a reaction product with diethylene triamine In areaction flask similar to that of Example III, a mixture of 3000 grams(0.697 mole) of a polypropylphenoxybutyric acid containing 60% mineraloil (prepared in the same manner as in Example II, having an acid numberof 13 mgm. KOH per gram of oil-diluted product), 139 grams (1.35 moles)of diethylene triamine, and 1200 ml. of xylene was heated to reflux forabout hours at 167 C. Water distillate was collected in a Dean-Starktake-off tube. An additional 2000 ml. of xylene were added and theresulting xylene solution was washed with 1500 ml. portions of hot,distilled water, until the washings were neutral to litmus. Xylene wasdistilled to 175 C. at 130 mm. Hg and then to 175 C. at 7 mm. Hg.

The product was analyzed, with the following results:

Total nitrogen=0.62%. Basic nitrogen=0.30%. Acid number=0.96 mgm. KOHper gram of product.

During the water removal in this example, the amount collected exceededthat amount expected for producing a simple amide. Infrared spectrumanalysis indicated the presence of an imidazoline product.

ENGINE TESTS OF REACTION PRODUCTS (1) Caterpillar Engine Test.-Theability of the reaction products, namely the esters, amides, andimidazolines of this invention, to perform as lubricating oil detergentshas been shown by using oils blended with minor amounts of theseproducts in the Caterpillar Engine Test.

The Caterpillar Engine Test measures the ability of an oil to preventdeposits on the piston. The grooves, lands, and skirts of the piston areexamined for thickness, density and amount of deposits; the degree oflacquer formation is also determined. The amount and quality of depositsare reduced to numerical demerits. The total rating is the total numberof demerits subtracted from 100, a rating of 100 signifying a perfectlyclean piston. The lacquer demerits (Lac.) indicate the amount of lacquerformation below the top ring groove, The top groove packing (percentTGP) shows the percent of top groove volume behind the piston ring thatis filled with carbon.

The test oil samples consist of a solvent-refined mineral oil, having anSUV. 210 F. of 64.1, blended with 7% by weight of the total blend ofeach of the products of Examples III, IV, and V, respectively and 1% ofa zinc dithiophosphate antioxidant. The engines were run on a dieselfuel containing 1% sulfur. A single cylinder, 4-cycle Caterpillar engineis used under the following operating conditions:

Oil temperature, F 150 Jacket temperature, F. 180

Speed, r.p.m 1000 Brake load, H.P 19.8

6 The duration of the test varied in each case. The results obtained aretabulated below:

(2) Low Temperature Deposit Test (Gasoline Engine).-A lubricating oilblend containing 7% by weight of the total blend of Example III and 1%of a zinc dithiophosphate antioxidant was tested in a second engine. Inthis test the ability of the oil to prevent low-temperature depositsfrom forming is investigated. The one-cylinder CLR Oil Test Engine isoperated on a specific fuel prepared for this test, CRC Designation RMF215-59 containing about 0.21% sulfur. The engine is run at a lowtemperature for 3 hours and at a high temperature for 1 hourconsecutively for a total duration of hours. The following engineconditions are maintained:

3-Hour l-Hour Low High Temp. Temp. Cycle Cycle Speed, r.p.m 1, 800 1,800 Fuel Flow, lb./hr 4. 7 4. 7 Water Temperature, F 120 200 Variousparts of the engine are checked for total sludge or deposits, andparticularly deposits around the piston skirt, oil rings, and oilscreen. The results are rated according to the CRC Deposit Rating Scale.

It will be seen from the data of these two engine tests that theproducts of this invention are effective lubricating oil detergents.From about 1% to 10%, by weight, of the total lubricating composition ofthe esters, amides, alkanolamides, and imidazoline compounds may beemployed. The oil compositions may also contain other addition agentssuch as pour point depressants, viscosity index improvers, and the like.

Although the present invention has been described herein by specificembodiments and illustrative examples, it is not intended that the scopeof the present invention be limited thereby, except as indicated in thefollowing claims.

I claim:

1. A lubricating oil composition comprising a major proportion of alubricating oil and a minor proportion suflicient to provide detergentproperties thereto of a compound prepared by (1) the reaction of analkali metal salt of a polyalkylenephenol having the formula:

wherein R is a polyalkylene radical selected from the group consistingof polypropylene, polybutene, and polyisobutylene having a molecularweight in the range of about 500 to 3000, with an aliphatic lactonehaving from 2 to about 20 carbon atoms, thereby forming apolyalkylenephenoxymonocarboxylic acid compound; and (2) the reaction ofsaid acid compound with an alkanolamine having from 1 to about 20 carbonatoms.

2. The composition of claim 1, wherein the aliphatic compound isselected from the group consisting of diethanolarnine andtriethanolarnine.

3. The composition of claim 1, wherein the said polyalkylene radical isa polypropylene having a molecular weight'in the range of 750 to 850.

4. The composition of claim 1, wherein the said compound is apolypropylphenoxybutyric acid-diethanolarnine reaction product.

5. The composition of claim 1, wherein the said compound is apolypropylphenoxybutyric acid-triethanolamine reaction product.

References Cited UNITED STATES PATENTS Reifi" et a1 252-57 X Prutton25257 X Neely 25257 Preston et a1 25257 X Stuart'et a1. 25251.5 X

DANIEL E. WYMAN, Primary Examiner.

1. A LUBRICATING OIL COMPOSTION COMPRISING A MAJOR PROPORTION OF ALUBRICATING OIL AND A MINOR PROPORTION SUFFIEIENT TO PROVIDE DETERGENTPROPERTIES THERETO OF A COMPOUND PREPARED BY (1) THE REACTION OF ANALKALI METAL SALT OF A POLYALKYLENEPHENOL HAVING THE FORMULA: